Gabriela Kohr
University of Toronto
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Featured researches published by Gabriela Kohr.
Archive | 2003
Ian D. Graham; Gabriela Kohr
Univalent functions: elementary properties of univalent functions Subclasses of univalent functions in the unit disc The Loewner theory Bloch functions and the Bloch constant Linear invariance in the unit disc Univalent mappings in several complex variables and complex Banach spaces Univalence in several complex variables Growth, covering and distortion results for starlike and convex mappings in Cn and complex Banach spaces Loewner chains in several complex variables Bloch constant problems in several complex variables Linear invariance in several complex variables Univalent mappings and the Roper-Suffridge extension operator.
Journal D Analyse Mathematique | 2000
Ian D. Graham; Gabriela Kohr
The Roper-Suffridge extension operator provides a way of extending a (locally) univalent functionfεH(U) to a (locally) biholomorphic mappingF∈H(Bn). In this paper, we give a simplified proof of the Roper-Suffridge theorem: iff is convex, then so isF. We also show that iff∈S*, theF is starlike and that iff is a Bloch function inU, thenF is a Bloch mapping onBn. Finally, we investigate some open problems.
Complex Variables | 2002
Ian D. Graham; Gabriela Kohr
Let B be the unit ball in C n and let U be the unit disc in C. The aim of this work is to construct a family of operators Ψ n,α that provide a way to extend a locally univalent function ƒ ∈ H(U) to a locally univalent mapping Fα ∈ H(B), where α ∈ (0,1]. If ƒ is normalized univalent, then Fα can be imbedded in a Loewner chain. Also if ƒ ∈ S*, then Fα is starlike. We show that if ƒ belongs to a class of univalent functions which satisfy growth and distortion results, then the mapping Fα satisfies similar growth and distortion results. Also we study the concept of linear-invariant families as it relates to families generated by the operator Ψ n,0, and we obtain in this way another example of a L.I.F. that has minimum order (n + 1)/2 and is not a subset of the normalized convex mappings in the unit ball of C n (for n ≤ 2.)
Complex Variables and Elliptic Equations | 1998
Gabriela Kohr
In this paper we obtain the best estimations for some coefficients of several subclasses of biholomorphic mappings defined on the unit ball of . As a consequence, we give some bounds for coefficients of starlike, starlike of order a e (0,1) and convex mappings on the unit ball of .
Complex Variables | 2002
Hidetaka Hamada; Gabriela Kohr
In this paper, we obtain the growth result for normalized convex mappings on the unit ball of a complex Banach space. Also we give some bounds of coefficients and a distortion result for convex mappings on the unit ball of a complex Hilbert space.
Journal D Analyse Mathematique | 2005
Hidetaka Hamada; Gabriela Kohr
AbstractLetf(z, t) be a subordination chain fort ∈ [0, α], α>0, on the Euclidean unit ballB inCn. Assume thatf(z) =f(z, 0) is quasiconformal. In this paper, we give a sufficient condition forf to be extendible to a quasiconformal homeomorphism on a neighbourhood of
Complex Variables and Elliptic Equations | 2001
Hidetaka Hamada; Gabriela Kohr
International Journal of Mathematics and Mathematical Sciences | 2003
Gabriela Kohr
\bar B
Transactions of the American Mathematical Society | 2011
Peter Duren; Hidetaka Hamada; Gabriela Kohr
Complex Variables | 2005
Hidetaka Hamada; Gabriela Kohr; Mirela Kohr
. We also show that, under this condition,f can be extended to a quasiconformal homeomorphism of